134a what size orifice

[chris989]

Hello all,
1989 v2500 suburban

While chasing a leak,, I installed a new fixed white orifice and now the low pressure is a little high and it will not pull temps lower the ~60 at the vent.

I pulled out a VOV valve that was a little dirty and did not take note of the color.

I am thinking of pumping back down and installing a .067.

What did others use? How many Ounces of 134 did you use?

Thanks,
Chris

[v30crewcab]

the .067 should work good. I think thats what is in my truck.

[chris989]

I reinstalled the VOV
https://www.napaonline.com/en/p/TEM207325

i have 42-48 degrees at the vent

[Hart_Rod]

Originally Posted by chris989

I reinstalled the VOV
https://www.napaonline.com/en/p/TEM207325

i have 42-48 degrees at the vent

Just curious why did you chose that one?

[hatzie]

I've used the .067" Ford Blue orifice tubes and VOV for R12 to R134a conversions. The C4 Vette guys prefer the Ford Blue tubes rather than the VOV.
Variable orifice valves have been hit or miss for me as they aged. I used to recommend them. I've come to the conclusion that moving parts are not a great thing for long term reliability.

[v30crewcab]

whats the part # for the ford blue tube?

[hatzie]

Four Seasons 38621

[chris989]

Originally Posted by Hart_Rod

Just curious why did you chose that one?

It is what I used when i swapped from 12 to 134. I only went white fixed because I had it on the shelf and that is what is called for.

I am using a Sanden SD7,, With the fixed i could not get decent temps.. My motor runs around 2,000 or less in town.

Chris

[hatzie]

Originally Posted by chris989

It is what I used when i swapped from 12 to 134. I only went white fixed because I had it on the shelf and that is what is called for.

I am using a Sanden SD7,, With the fixed i could not get decent temps.. My motor runs around 2,000 or less in town.

Chris

The white GM orifice is 0.072
That's just fine for hydrocarbon R290 and R12.

You need a slightly smaller orifice for R134a and HFC152.
As I said the Ford blue is 0.067 and it seems to do the job.

[Hart_Rod]

Originally Posted by chris989

It is what I used when i swapped from 12 to 134. I only went white fixed because I had it on the shelf and that is what is called for.

I am using a Sanden SD7,, With the fixed i could not get decent temps.. My motor runs around 2,000 or less in town.

Chris

Originally Posted by hatzie

The white GM orifice is 0.072
That's just fine for hydrocarbon R290 and R12.

You need a slightly smaller orifice for R134a and HFC152.
As I said the Ford blue is 0.067 and it seems to do the job.

Gotcha. I talked to a local Hotrodder than runs an AC shop. He recommended the white one, so that's what I used when I did the LT swap in my 84 (Sanden compressor/134A). So far, it cools great with no issues. Hatzie - what symptoms should I look out for that might suggest that I switch to the blue one?

[hatzie]

Originally Posted by Hart_Rod

Gotcha. I talked to a local Hotrodder than runs an AC shop. He recommended the white one, so that's what I used when I did the LT swap in my 84 (Sanden compressor/134A). So far, it cools great with no issues. Hatzie - what symptoms should I look out for that might suggest that I switch to the blue one?

Higher vent temps when you're in traffic with the engine idling or near idling.
If your set up is working I'd stick with it.

[Hart_Rod]

Originally Posted by hatzie

Higher vent temps when you're in traffic with the engine idling or near idling.
If your set up is working I'd stick with it.

Thanks. Will report back if I see any changes.

Rob